1. Field of the Invention
The present invention relates to the transmit power of a wireless communication system. More particularly, the present invention relates to a method and apparatus for controlling the transmit power of a mobile Base Station (BS) in a wireless communication environment.
2. Description of the Related Art
In the construction of a cellular communication system, cell planning is used to determine points where BSs are to be deployed in order to maximize efficiency while minimizing costs. That is, cell planning is used to determine BS deployment points based on a transmit/receive power strength analysis, a test call generation function analysis, a cell coverage analysis and diagnosis, an operation environment analysis, an inter-BS interference analysis, a local feature dependent propagation characteristic analysis, and the like.
Generally, in a cellular communication system, a fixed BS is installed and operated in the outdoors to maintain a service coverage area centered on the BS deployment point that is determined based on the cell planning. That is, during network design for the outdoor installation of the fixed BS, cells are classified diversely in size according to a peripheral topography or feature, the number of users, etc. and the cellular communication system is adaptively operated. Prior to BS deployment, a Code Division Multiple Access (CDMA) system or Worldwide Interoperability for Microwave Access (WiMAX)-class system that is now in commercial use determines a BS position based on the maximum transmit power of a fixed BS such that the fixed BS has the maximum capacity within a certain coverage area through network design of a network optimization process.
On the other hand, in a military communication environment, a location for deployment of a fixed BS cannot be determined because military units are mobile and can move to various regions such as a training region, whereas a legacy power control technique determines a position of a BS to have the maximum capacity within a fixed coverage area based on the maximum transmit power. In other words, a legacy power control technique cannot be used in the military communication environment where BSs in addition to user Mobile Stations (MSs) are mobile. For example, a wireless environment suffers a substantial change according to a position of a BS and therefore, in case that all BSs identically transmit downlink data to an MS at the maximum transmit power as in the general cellular communication system, in a situation in which mobile BSs neighbor one another, two BSs act as substantial interference to each other, thus resulting in the deterioration of system performance.
As described above, in case that a mobile BS transmits at the maximum transmit power without transmit power control and without considering a peripheral wireless environment, it can result in substantial interference in a legacy network.
Accordingly, there is a need for a method and apparatus for controlling the transmit power of a mobile BS in a wireless communication system.